This PR demonstrates one way in-world editing of objects might work. 

Running this script will show light overlay icons in-world.  Enter edit mode by running your distance beam through a light overlay.  Exit using the red X.

When you distant grab the sliders, you can move them along their axis to change their values.  You may also rotate / move the block to which the spotlight is attached.  

To test: https://rawgit.com/imgntn/hifi/light_mod/examples/lights/lightLoader.js
To reset, I recommend stopping all scripts then re-loading lightLoader.js

When you run the lightLoader.js script, several scripts will be loaded:
- handControllerGrab.js (will not impart velocity when you move the parent or a slider, will not move sliders with head movement,will constrain movement for a slider to a given axis start and end, will support blacklisting of entities for raypicking during search for objects)
- lightModifier.js (listens for message to create sliders for a given light.  will start with slider set to the light's initial properties)
- lightModifierTestScene.js (creates a light)
- slider.js (attached to each slider entity)
- lightParent.js (attached to a 3d model of a light, to which a light is parented, so you can move it around.  or keep the current parent if a light already has a parent)
- visiblePanel.js (the transparent panel)
- closeButton.js (for closing the ui)
- ../libraries/lightOverlayManager.js (shows 2d overlays for lights in the world)
- ../libraries/entitySelectionTool.js (visualizes volume of the lights)

Current sliders are (top to bottom):
red
green
blue
intensity
cutoff
exponent

![capture](https://cloud.githubusercontent.com/assets/843228/11910139/afaaf1ae-a5a5-11e5-8b66-0eb3fc6976df.PNG)